数据结构--数组模拟队列

#include<iostream>
using namespace std;
const int N=1e5+10;
int m;
int head=0,tail=-1;
int q[N];
int main(void){
    int m;
    cin>>m;
    for(int i=0;i<m;i++){
        string op;
        int x;
        cin>>op;
        if(op=="push"){
            cin>>x;
            q[++tail]=x;
        }else if(op=="pop"){
            head++;
        }else if(op=="empty"){
            if(tail<head){
                cout<<"YES"<<endl;
            }else{
                cout<<"NO"<<endl;
            }
        }else if(op=="query"){
            cout<<q[head]<<endl;
        }
    }
    return 0;
}